A back-illuminated solid-state imaging device having a three-dimensional structure has in recent years been proposed in which a circuit substrate on which a drive circuit is formed is attached to an opposite surface from a light receiving surface of a semiconductor substrate on which pixels including a photoelectric conversion unit are formed (see, for example, Patent Literature 1). Such a solid-state imaging device having a three-dimensional structure includes a connection electrode for electrically connecting the semiconductor substrate and the circuit substrate together.
FIG. 1 is a cross-sectional view showing an example configuration of a conventional back-illuminated solid-state imaging device having a three-dimensional structure.
In FIG. 1, a circuit substrate 11 and a semiconductor substrate 12 are attached together, and are electrically connected together by a connection electrode 13. Also, an insulating film 14 is formed on a light receiving surface side (an upper side in FIG. 1) of the semiconductor substrate 12.
In the solid-state imaging device shown in FIG. 1, the insulating film 14 is formed so that the height of a cross-section (hereinafter also referred to as a “cross-sectional height”) of a pixel region where a plurality of pixels are provided, and the height of a cross-section of a peripheral region which is outside an interconnection region where the connection electrode 13 is provided, are smaller than the height of a cross-section of the interconnection region. By thus reducing the profile of the pixel region, sensitivity characteristics or color mixture characteristics can be improved. Also, by reducing the profile of the pixel region, constraints on the arrangement of circuit interconnects or alignment marks in the peripheral region can be relaxed, and stress on the substrate can be reduced.